user: ### NOW ANSWER:
Question: what is the grid when the time/retired is oil pressure and the laps are more than 50?
Columns: ['Driver', 'Constructor', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Jackie Stewart', 'Tyrrell - Ford', 55.0, '1:46:42.3', 1.0]
SQL:

assistant: SELECT AVG("Grid") FROM "Table" WHERE "Time/Retired" = 'oil pressure' AND "Laps" > 50.0;