user: Question: What was the date of the poll with a sample size of 496 where Republican Mike Huckabee was chosen?
Columns: ['Poll Source', 'Sample Size', 'Margin of Error', 'Date', 'Democrat', 'Republican']
Types: ['text', 'real', 'real', 'text', 'text', 'text']
Sample row: ['Quinnipiac', 1528.0, 2.5, 'Mar 16-18, 2008', 'Hillary Clinton', 'John McCain']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Republican" = 'Mike Huckabee' AND "Sample Size" = 496.0;