CREATE TABLE table_49703 ("Res." TEXT, "Record" TEXT, "Opponent" TEXT, "Method" TEXT, "Round" FLOAT)

How many rounds is the fight against Michael Chavez?
SELECT AVG("Round") FROM table_49703 WHERE "Opponent" = 'michael chavez'
SELECT AVG("Round") FROM "table_49703" WHERE "Opponent" = 'michael chavez'