user: Question: Which stage took the tour through Boulogne-Billancourt?
Columns: ['Stage', 'Date', 'Route', 'Terrain', 'Length', 'Winner']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['P', '4 July', 'Boulogne-Billancourt', 'Individual time trial', 'km (mi)', 'Thierry Marie ( FRA )']
SQL:

assistant: SELECT "Stage" FROM "Table" WHERE "Route" = 'Boulogne-Billancourt';