user: Question: Which surface has a Date of 22 August 2006?
Columns: ['Outcome', 'Date', 'Tournament', 'Surface', 'Opponent', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', '23 August 2004', 'Maribor , Slovenia', 'Clay', 'Maša Zec Peškirič', '6–2, 7–5']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Date" = '22 August 2006';