Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What time/retired for a grid less than 19, under 21 laps, and made by aprilia?

### Inputs:
table_name: table, columns: ['Rider', 'Manufacturer', 'Laps', 'Time/Retired', 'Grid']

### Response:
SELECT Time/Retired FROM table WHERE Grid < 19 AND Manufacturer = aprilia AND Laps < 21