CREATE TABLE table_name_15 (round INT, res VARCHAR, opponent VARCHAR)

Name the Round that has Res of win and an Opponent of demian maia?
SELECT SUM(round) FROM table_name_15 WHERE res = "win" AND opponent = "demian maia"
SELECT SUM("round") FROM "table_name_15" WHERE "demian maia" = "opponent" AND "res" = "win"