Table: motorsport_deaths
Columns: discipline
championship
circuit
event
session

Question: For the USAC National Championship, what is the Discipline?
SQL: SELECT "discipline" FROM motorsport_deaths WHERE "championship" = 'usac national championship'

Question: In the Indianapolis Sweepstakes race session, what is the championship?
SQL: SELECT "championship" FROM motorsport_deaths WHERE "session" = 'race' AND "event" = 'indianapolis sweepstakes'

Question: What circuit is the Sprint Cup series championship?
SQL: SELECT "circuit" FROM motorsport_deaths WHERE "championship" = 'sprint cup series'