user: Question: Tell me the opponents for Runner-up and surface of Grass
Columns: ['Outcome', 'Date', 'Tournament', 'Surface', 'Partner', 'Opponents in the final']
Types: ['text', 'real', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', 1968.0, 'Barcelona , Spain', 'Clay', 'José Mandarino', 'Carlos Fernández Patricio Rodríguez']
SQL:

assistant: SELECT "Opponents in the final" FROM "Table" WHERE "Outcome" = 'Runner-up' AND "Surface" = 'Grass';