user: Question: For the USAC National Championship, what is the Discipline?
Columns: ['Discipline', 'Championship', 'Circuit', 'Event', 'Session']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Stock car', 'Sprint Cup Series', 'Daytona International Speedway', 'UNO Twin 125 Qualifiers', 'Qualifying']
SQL:

assistant: SELECT "Discipline" FROM "Table" WHERE "Championship" = 'USAC National Championship';