Table: qatar_tour_2010
Columns: stage
winner
general_classification
points_classification
young_rider_classification
teams_classification

Question: What is the number of stages where the teams classification leader is Cervélo Testteam?
SQL: SELECT COUNT("stage") FROM qatar_tour_2010 WHERE "teams_classification" = 'Cervélo TestTeam'

Question: How many stages did Team Sky lead the teams classification?
SQL: SELECT MAX("stage") FROM qatar_tour_2010 WHERE "teams_classification" = 'Team Sky'

Question: Who leads the general classification in stage 3?
SQL: SELECT "general_classification" FROM qatar_tour_2010 WHERE "stage" = 3