user: Question: Name the Surface that of Tournament of Valencia , Spain?
Columns: ['Date', 'Tournament', 'Surface', 'Partnering', 'Opponent in the final', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['August 16, 2004', 'Washington, D.C. , United States', 'Hard', 'Dmitry Tursunov', 'Chris Haggard Robbie Koenig', '7–6 3 , 6–1']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Tournament" = 'Valencia , Spain';