CREATE TABLE table_66811 ("Year" FLOAT, "Team" CLOB, "Co-Drivers" CLOB, "Class" CLOB, "Laps" FLOAT, "Pos." CLOB, "Class Pos." CLOB)

Which Class has Laps of 31?
SELECT "Class" FROM table_66811 WHERE "Laps" = '31'
SELECT "Class" FROM "table_66811" WHERE "Laps" = '31'