CREATE TABLE table_48352 ("Discipline" CLOB, "Championship" CLOB, "Circuit" CLOB, "Event" CLOB, "Session" CLOB)

For the USAC National Championship, what is the Discipline?
SELECT "Discipline" FROM table_48352 WHERE "Championship" = 'usac national championship'
SELECT "Discipline" FROM "table_48352" WHERE "Championship" = 'usac national championship'