user: Question: When 19 is the stage who is the points classification?
Columns: ['Stage', 'Winner', 'General classification', 'Points classification', 'Mountains classification', 'Young rider classification']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Team Columbia-High Road', 'Mark Cavendish', 'no award', 'no award', 'Mark Cavendish']
SQL:

assistant: SELECT "Points classification" FROM "Table" WHERE "Stage" = 19.0;