user: Question: Name the partner for surface of Grass and opponents of Jürgen Melzer Philipp Petzschner
Columns: ['Outcome', 'Date', 'Surface', 'Partner', 'Opponents in the final', 'Score in the final']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', 'May 17, 2009', 'Clay', 'Andrei Pavel', 'Marcelo Melo André Sá', '7–6 (11–9) , 2–6, [7–10]']
SQL:

assistant: SELECT "Partner" FROM "Table" WHERE "Surface" = 'Grass' AND "Opponents in the final" = 'Jürgen Melzer Philipp Petzschner';