user: Question: How many different people had a General Classification on Stage 5?
Columns: ['Stage', 'Winner', 'General classification', 'Mountains Classification', 'Points classification', 'Sprints Classification', 'Team Classification']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Fabian Cancellara', 'Fabian Cancellara', 'no award', 'Fabian Cancellara', 'no award', 'Liquigas-Doimo']
SQL:

assistant: SELECT COUNT("General classification") FROM "Table" WHERE "Stage" = 5.0;