diff --git a/backend/open_webui/migrations/versions/b10670c03dd5_update_user_table.py b/backend/open_webui/migrations/versions/b10670c03dd5_update_user_table.py
index ba2ab26cca..34e0e27068 100644
--- a/backend/open_webui/migrations/versions/b10670c03dd5_update_user_table.py
+++ b/backend/open_webui/migrations/versions/b10670c03dd5_update_user_table.py
@@ -72,7 +72,6 @@ def _convert_column_to_json(table: str, column: str):
     dialect = conn.dialect.name
 
     t = sa.table(table, sa.column('id', sa.Text), sa.column(column, sa.Text))
-    t_json = sa.column(f'{column}_json', sa.JSON)
 
     # SQLite cannot ALTER COLUMN → must recreate column
     if dialect == 'sqlite':
@@ -90,9 +89,11 @@ def _convert_column_to_json(table: str, column: str):
                     parsed = None
 
             conn.execute(
-                sa.update(sa.table(table, sa.column('id'), t_json))
+                sa.update(
+                    sa.table(table, sa.column('id'), sa.column(f'{column}_json', sa.JSON))
+                )
                 .where(sa.column('id') == uid)
-                .values({f'{column}_json': json.dumps(parsed) if parsed else None})
+                .values({f'{column}_json': parsed})
             )
 
         op.drop_column(table, column)
@@ -112,8 +113,7 @@ def _convert_column_to_text(table: str, column: str):
     conn = op.get_bind()
     dialect = conn.dialect.name
 
-    t = sa.table(table, sa.column('id', sa.Text), sa.column(column))
-    t_text = sa.column(f'{column}_text', sa.Text)
+    t = sa.table(table, sa.column('id', sa.Text), sa.column(column, sa.JSON))
 
     if dialect == 'sqlite':
         op.add_column(table, sa.Column(f'{column}_text', sa.Text(), nullable=True))
@@ -122,9 +122,11 @@ def _convert_column_to_text(table: str, column: str):
 
         for uid, raw in rows:
             conn.execute(
-                sa.update(sa.table(table, sa.column('id'), t_text))
+                sa.update(
+                    sa.table(table, sa.column('id'), sa.column(f'{column}_text', sa.Text))
+                )
                 .where(sa.column('id') == uid)
-                .values({f'{column}_text': json.dumps(raw) if raw else None})
+                .values({f'{column}_text': json.dumps(raw) if raw is not None else None})
             )
 
         op.drop_column(table, column)