Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Rider | Manufacturer | Laps | Time | Grid |
| --- | --- | --- | --- | --- |
| Mika Kallio | KTM | 21.0 | 48:12.217 | 3.0 |
| Hiroshi Aoyama | KTM | 21.0 | +3.238 | 11.0 |
| Mattia Pasini | Aprilia | 21.0 | +13.811 | 7.0 |
| Marco Simoncelli | Gilera | 21.0 | +18.474 | 5.0 |
| Alex Debon | Aprilia | 21.0 | +21.066 | 12.0 |
| Hector Barbera | Aprilia | 21.0 | +25.158 | 2.0 |
| Yuki Takahashi | Honda | 21.0 | +29.900 | 10.0 |
| Ratthapark Wilairot | Honda | 21.0 | +39.871 | 18.0 |
| Aleix Espargaro | Aprilia | 21.0 | +48.344 | 15.0 |
| Héctor Faubel | Aprilia | 21.0 | +55.470 | 13.0 |
| Roberto Locatelli | Gilera | 21.0 | +55.832 | 9.0 |
| Alvaro Bautista | Aprilia | 21.0 | +1:00.442 | 1.0 |
| Eugene Laverty | Aprilia | 21.0 | +1:00.732 | 19.0 |
| Fabrizio Lai | Gilera | 21.0 | +1:36.975 | 16.0 |
| Doni Tata Pradita | Yamaha | 21.0 | +1:37.080 | 21.0 |
| Imre Toth | Aprilia | 21.0 | +1:45.018 | 22.0 |
| Russel Gomez | Aprilia | 21.0 | +2:13.718 | 23.0 |
| Alex Baldolini | Aprilia | 14.0 | Retirement | 20.0 |
| Julian Simon | KTM | 5.0 | Retirement | 4.0 |
| Thomas Luthi | Aprilia | 5.0 | Retirement | 6.0 |
| Karel Abraham | Aprilia | 4.0 | Retirement | 17.0 |
| Lukas Pesek | Aprilia | 2.0 | Retirement | 14.0 |
| Manuel Poggiali | Gilera | 0.0 | Accident | 8.0 |
Question:
what is the time when laps is less than 21, manufacturer is aprilia, grid is less than 17 and the rider is thomas luthi?
Answer:
Retirement