user: ### NOW ANSWER:
Question: Which Original air date has a Season # smaller than 21, and a Title of "Palimpsest"?
Columns: ['Series #', 'Season #', 'Title', 'Directed by', 'Original air date']
Types: ['real', 'real', 'text', 'text', 'text']
Sample row: [45.0, 1.0, '"Jaunt (Part 2)"', 'John Bell', 'September 27, 1998']
SQL:

assistant: SELECT "Original air date" FROM "Table" WHERE "Season #" < 21.0 AND "Title" = '"Palimpsest"';