user: Question: What is the surface on 15 August 2009?
Columns: ['Outcome', 'Date', 'Tournament', 'Surface', 'Partner', 'Opponents', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', '22 March 2004', 'Portugal F2, Albufeira , Portugal', 'Hard', 'Leonardo Tavares', 'Juan Ignacio Cerda & Jasper Smit', '6–4, 6–4']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Date" = '15 August 2009';