user: Question: Andy Roddick is the opponent in the final on what surface?
Columns: ['Outcome', 'No.', 'Date', 'Championship', 'Surface', 'Opponent in the final', 'Score in the final']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Winner', '23.', 'January 9, 2005', 'Doha , Qatar', 'Hard', 'Ivan Ljubičić', '6–3, 6–1']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Opponent in the final" = 'Andy Roddick';