user: Question: Who played on Clay on 3 March 2012?
Columns: ['Date', 'Tournament', 'Surface', 'Opponent', 'Score']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['17 May 2004', 'Verona', 'Clay', 'Alex Vittur', '6–1, 7–6']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Surface" = 'Clay' AND "Date" = '3 March 2012';