user: Question: What time/retired for a grid less than 19, under 21 laps, and made by Aprilia?
Columns: ['Rider', 'Manufacturer', 'Laps', 'Time/Retired', 'Grid']
Types: ['text', 'text', 'real', 'text', 'real']
Sample row: ['Álvaro Bautista', 'Aprilia', 21.0, '40:18.605', 1.0]
SQL:

assistant: SELECT "Time/Retired" FROM "Table" WHERE "Grid" < 19.0 AND "Manufacturer" = 'Aprilia' AND "Laps" < 21.0;