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:
| Stage | Date | Route | Terrain | Length | Winner |
| --- | --- | --- | --- | --- | --- |
| P | 29 June | Leiden | Individual time trial | 5 km (3.1 mi) | Jan Raas (NED) |
| 1A | 30 June | Leiden – St Willebrord | Plain stage | 135 km (84 mi) | Jan Raas (NED) |
| 1B | 30 June | St Willebrord – Brussel | Plain stage | 100 km (62 mi) | Walter Planckaert (BEL) |
| 2 | 1 July | Brussel – St Amand les Eaux | Plain stage | 199 km (124 mi) | Jacques Esclassan (FRA) |
| 3 | 2 July | St Amand les Eaux – St Germain en Laye | Plain stage | 244 km (152 mi) | Klaus-Peter Thaler (GER) |
| 4 | 3 July | Evreux – Caen | Team time trial | 153 km (95 mi) | TI-Raleigh |
| 5 | 4 July | Caen – Maze Montgeoffroy | Plain stage | 244 km (152 mi) | Freddy Maertens (BEL) |
| 6 | 5 July | Maze Montgeoffroy – Poitiers | Plain stage | 162 km (101 mi) | Sean Kelly (IRE) |
| 7 | 6 July | Poitiers – Bordeaux | Plain stage | 242 km (150 mi) | Freddy Maertens (BEL) |
| 8 | 7 July | St Emilion – Ste Foy la Grande | Individual time trial | 59 km (37 mi) | Bernard Hinault (FRA) |
| 9 | 8 July | Bordeaux – Biarritz | Plain stage | 233 km (145 mi) | Miguel Maria Lasa (ESP) |
| 10 | 10 July | Biarritz – Pau | Hilly stage | 192 km (119 mi) | Henk Lubberding (NED) |
| 11 | 11 July | Pau – St Lary Soulan | Stage with mountain(s) | 161 km (100 mi) | Mariano Martínez (FRA) |
| 12A | 12 July | Tarbes – Valence d'Agen | Plain stage | 158 km (98 mi) | Cancelled |
| 12B | 12 July | Valence d'Agen – Toulouse | Plain stage | 96 km (60 mi) | Jacques Esclassan (FRA) |
| 13 | 13 July | Figeac – Super Besse | Hilly stage | 221 km (137 mi) | Paul Wellens (BEL) |
| 14 | 14 July | Besse en Chandesse – Puy de Dôme | Individual time trial | 52 km (32 mi) | Joop Zoetemelk (NED) |
| 15 | 15 July | St Dier d'Auvergne – St Etienne | Hilly stage | 196 km (122 mi) | Bernard Hinault (FRA) |
| 16 | 16 July | St Etienne – L'Alpe d'Huez | Stage with mountain(s) | 241 km (150 mi) | Hennie Kuiper (NED) |
| 17 | 18 July | Grenoble – Morzine | Stage with mountain(s) | 225 km (140 mi) | Christian Seznec (FRA) |
| 18 | 19 July | Morzine – Lausanne | Plain stage | 137 km (85 mi) | Gerrie Knetemann (NED) |
| 19 | 20 July | Lausanne – Belfort | Plain stage | 182 km (113 mi) | Marc Demeyer (BEL) |
| 20 | 21 July | Metz – Nancy | Individual time trial | 72 km (45 mi) | Bernard Hinault (FRA) |
| 21 | 22 July | Epernay – Senlis | Plain stage | 207 km (129 mi) | Jan Raas (NED) |
| 22 | 23 July | St Germain en Laye – Paris (Champs-Élysées) | Plain stage | 162 km (101 mi) | Gerrie Knetemann (NED) |
Question:
name the only stage that sean kelly won.
Answer:
6