CREATE TABLE table_31838 ("Res." CLOB, "Record" CLOB, "Opponent" CLOB, "Method" CLOB, "Event" CLOB, "Round" FLOAT, "Time" CLOB, "Location" CLOB)

Tell me the lowest round for total combat 15
SELECT MIN("Round") FROM table_31838 WHERE "Event" = 'total combat 15'
SELECT MIN("Round") FROM "table_31838" WHERE "Event" = 'total combat 15'