user: Question: What was the Surface for the Partner of Jürgen Melzer, and a Date of July 16, 2011?
Columns: ['Outcome', 'Date', 'Surface', 'Partner', 'Opponents', 'Score']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', 'October 12, 2008', 'Hard (i)', 'Alexander Peya', 'Max Mirnyi Andy Ram', '1–6, 5–7']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Partner" = 'Jürgen Melzer' AND "Date" = 'July 16, 2011';