user: Question: Who was the partner that played a match on a Grass court?
Columns: ['Outcome', 'Date', 'Surface', 'Partner', 'Opponents', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Winner', 'July 7, 2008', 'Grass', 'Mardy Fish', 'Rohan Bopanna Aisam-ul-Haq Qureshi', '6–4, 7–6 (7–1)']
SQL:

assistant: SELECT "Partner" FROM "Table" WHERE "Surface" = 'Grass';