diff --git a/lilac/data/dataset_duckdb.py b/lilac/data/dataset_duckdb.py
index 61c4c61c..5307919a 100644
--- a/lilac/data/dataset_duckdb.py
+++ b/lilac/data/dataset_duckdb.py
@@ -3654,7 +3654,7 @@ def _replace_nan_with_none(df: pd.DataFrame) -> pd.DataFrame:
   # TODO(https://github.com/duckdb/duckdb/issues/4066): Remove this once duckdb fixes upstream.
   for col in df.columns:
     if is_object_dtype(df[col]):
-      df[col].replace(np.nan, None, inplace=True)
+      df[col] = df[col].replace(np.nan, None)
   return df