user: Question: Who was Betty's partner when the surface is Hard?
Columns: ['Outcome', 'Year', 'Championship', 'Surface', 'Partner', 'Opponents in the final', 'Score in the final']
Types: ['text', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Winner', 1972.0, 'French Open', 'Clay', 'Billie Jean King', 'Winnie Shaw Nell Truman', '6–1, 6–2']
SQL:

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