user: Question: Date of January 11, 1998 has what surface?
Columns: ['Date', 'Tournament', 'Surface', 'Opponent in the Final', 'Score']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['April 20, 1997', 'Tokyo, Japan', 'Hard', 'Amy Frazier', '4–6, 6–4, 6–4']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Date" = 'January 11, 1998';