user: Question: What was the Surface during the match with Partner Debbie Graham?
Columns: ['Outcome', 'Date', 'Tournament', 'Surface', 'Partner', 'Opponents', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', 'May 24, 1992', 'European Open , Switzerland', 'Clay', 'Karina Habšudová', 'Amy Frazier Elna Reinach', '5–7, 2–6']
SQL:

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