user: Question: On what Surface was the match against Ilija Bozoljac played?
Columns: ['Date', 'Tournament', 'Surface', 'Opponent', 'Score']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['5 September 2005', 'Brasov', 'Clay', 'Daniel Elsner', '5–7, 2–6']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Opponent" = 'Ilija Bozoljac';