diff --git a/colab_logica.py b/colab_logica.py
index 0703e92..ae2be13 100755
--- a/colab_logica.py
+++ b/colab_logica.py
@@ -189,9 +189,16 @@ def RunSQL(sql, engine, connection=None, is_final=False):
       psql_logica.PostgresExecute(sql, connection)
   elif engine == 'duckdb':
     if is_final:
-      return duckdb.sql(sql).df()
+      df = connection.sql(sql).df()
+      for c in df.columns:
+        if df.dtypes[c] == 'float64':
+          if df[c].isna().values.any():
+            return df
+          if set(df[c] - df[c].astype(int)) == {0.0}:
+            df[c] = df[c].astype(int)
+      return df
     else:
-      duckdb.sql(sql)
+      connection.sql(sql)
   elif engine == 'sqlite':
     try:
       if is_final:
@@ -229,7 +236,11 @@ def __call__(self, sql, engine, is_final):
 
 class DuckdbRunner(object):
   def __init__(self):
-    self.connection = duckdb_logica.SqliteConnect()
+    global DB_CONNECTION
+    if not DB_CONNECTION:
+      DB_CONNECTION = duckdb.connect()
+    self.connection = DB_CONNECTION
+
   def  __call__(self, sql, engine, is_final):
     return RunSQL(sql, engine, self.connection, is_final)
 
diff --git a/common/duckdb_logica.py b/common/duckdb_logica.py
index 1bd87ee..a12d16b 100644
--- a/common/duckdb_logica.py
+++ b/common/duckdb_logica.py
@@ -14,9 +14,5 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from decimal import Decimal
-import sqlite3
-
-def SqliteConnect():
-  con = sqlite3.connect(':memory:')
-  return con
\ No newline at end of file
+# Keeping the placeholder, but we may never needed.
+# DuckDB is too easy to connect!
\ No newline at end of file
diff --git a/compiler/universe.py b/compiler/universe.py
index 506ff6b..b924b5b 100755
--- a/compiler/universe.py
+++ b/compiler/universe.py
@@ -188,6 +188,11 @@ def Preamble(self):
           'create schema if not exists logica_home;\n'
           '-- Empty record, has to have a field by DuckDB syntax.\n'
           'drop type if exists logicarecord893574736 cascade; create type logicarecord893574736 as struct(nirvana numeric);\n'
+      )
+      if self.annotations['@Engine']['duckdb'].get('motherduck'):
+        preamble += '\n'  # Sequences are not supported in MotherDuck.
+      else:
+        preamble += (
           'create sequence if not exists eternal_logical_sequence;\n\n')
     return preamble
 
diff --git a/integration_tests/duckdb_flow_test.txt b/integration_tests/duckdb_flow_test.txt
index 12553c7..0fb09f5 100644
--- a/integration_tests/duckdb_flow_test.txt
+++ b/integration_tests/duckdb_flow_test.txt
@@ -1,18 +1,18 @@
-+------+------+--------------------+
-| col0 | col1 | logica_value       |
-+------+------+--------------------+
-| 0.0  | 1.0  | 2.9970000000000003 |
-| 0.0  | 4.0  | 9.994999999999997  |
-| 1.0  | 0.0  | 0.0                |
-| 1.0  | 2.0  | 0.0                |
-| 1.0  | 5.0  | 9.992999999999999  |
-| 2.0  | 1.0  | 6.995999999999998  |
-| 2.0  | 3.0  | 2.999              |
-| 2.0  | 4.0  | 0.0                |
-| 3.0  | 2.0  | 0.0                |
-| 3.0  | 5.0  | 0.0                |
-| 4.0  | 0.0  | 0.0                |
-| 4.0  | 2.0  | 9.994999999999997  |
-| 5.0  | 1.0  | 0.0                |
-| 5.0  | 3.0  | 9.992999999999999  |
-+------+------+--------------------+
\ No newline at end of file
++-------+-------+--------------------+
+| col0  | col1  | logica_value       |
++-------+-------+--------------------+
+| 0.000 | 1.000 | 2.9970000000000003 |
+| 0.000 | 4.000 | 9.994999999999997  |
+| 1.000 | 0.000 | 0.0                |
+| 1.000 | 2.000 | 0.0                |
+| 1.000 | 5.000 | 9.992999999999999  |
+| 2.000 | 1.000 | 6.995999999999998  |
+| 2.000 | 3.000 | 2.999              |
+| 2.000 | 4.000 | 0.0                |
+| 3.000 | 2.000 | 0.0                |
+| 3.000 | 5.000 | 0.0                |
+| 4.000 | 0.000 | 0.0                |
+| 4.000 | 2.000 | 9.994999999999997  |
+| 5.000 | 1.000 | 0.0                |
+| 5.000 | 3.000 | 9.992999999999999  |
++-------+-------+--------------------+
\ No newline at end of file
diff --git a/integration_tests/psqld_empty_list_type_duck_test.txt b/integration_tests/psqld_empty_list_type_duck_test.txt
index e053ebc..cb93a8b 100644
--- a/integration_tests/psqld_empty_list_type_duck_test.txt
+++ b/integration_tests/psqld_empty_list_type_duck_test.txt
@@ -1,5 +1,5 @@
 +--------------+
 | logica_value |
 +--------------+
-| nan          |
+| None         |
 +--------------+
\ No newline at end of file
diff --git a/logica.py b/logica.py
index deea994..d1be7cc 100755
--- a/logica.py
+++ b/logica.py
@@ -261,10 +261,9 @@ def main(argv):
                                         format).encode()
       elif engine == 'duckdb':
         import duckdb
-        df = duckdb.sql(formatted_sql).df()
-        o = sqlite3_logica.ArtisticTable(list(df.columns),
-                                         df.values
-                                         .tolist()).encode()
+        cur = duckdb.sql(formatted_sql)
+        o = sqlite3_logica.ArtisticTable(cur.columns,
+                                         cur.fetchall()).encode()
       elif engine == 'psql':
         connection_str = os.environ.get('LOGICA_PSQL_CONNECTION')
         if connection_str:
diff --git a/tools/run_in_terminal.py b/tools/run_in_terminal.py
index e11b70b..53d1070 100644
--- a/tools/run_in_terminal.py
+++ b/tools/run_in_terminal.py
@@ -105,8 +105,9 @@ def RunSQL(sql, engine, connection=None, is_final=False,
   elif engine == 'duckdb':
     import duckdb
     if is_final:
-      df = duckdb.sql(sql).df()
-      return list(df.columns), df.values.tolist()
+      import duckdb
+      cur = duckdb.sql(sql)
+      return cur.columns, cur.fetchall()
     else:
       duckdb.sql(sql)