user: Question: What is the name of the partner that has a Winner outcome and a Hard surface?
Columns: ['Outcome', 'Year', 'Championship', 'Surface', 'Partner', 'Opponents', 'Score']
Types: ['text', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', 2006.0, 'Berlin', 'Clay', 'Elena Dementieva', 'Yan Zi Zheng Jie', '2–6, 3–6']
SQL:

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