feat: update system prompt

app.py

@@ -49,7 +49,7 @@ def query_dataset(hub_repo_id, features, query):
     messages = [
         {
             "role": "system",
-            "content": "You are a helpful assistant that returns a DuckDB SQL query based on the user's query and dataset features. You might need to use DuckDB functions for lists and aggregations, given the features. Only return the SQL query, no other text.",
+            "content": "You are a SQL query expert assistant that returns a DuckDB SQL queries based on the user's natural language query and dataset features. You might need to use DuckDB functions for lists and aggregations, given the features. Only return the SQL query, no other text.",
         },
         {
             "role": "user",