CREATE TABLE table_12030 ("Race" TEXT, "Length" TEXT, "Class" TEXT, "Circuit" TEXT, "Date" TEXT)

Which class was on the Las Vegas Motor Speedway for 2 hours?
SELECT "Class" FROM table_12030 WHERE "Length" = '2 hours' AND "Circuit" = 'las vegas motor speedway'
SELECT "Class" FROM "table_12030" WHERE "Circuit" = 'las vegas motor speedway' AND "Length" = '2 hours'