CREATE TABLE table_36229 ("Res." TEXT, "Record" TEXT, "Opponent" TEXT, "Method" TEXT, "Event" TEXT, "Round" FLOAT, "Time" TEXT, "Location" TEXT)

How many rounds did the match go for the Bellator 72 event?
SELECT SUM("Round") FROM table_36229 WHERE "Event" = 'bellator 72'
SELECT SUM("Round") FROM "table_36229" WHERE "Event" = 'bellator 72'