user: Question: Which surface had Yew-Ming Si as a partner?
Columns: ['Date', 'Tournament', 'Surface', 'Partner', 'Opponents in the final', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['16 August 2004', 'Lahore', 'Grass', 'Vijay Kannan', 'Mirko Pehar & Toshiaki Sakai', '4–6 6–7']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Partner" = 'Yew-Ming Si';