CREATE TABLE table_48043 ("Round" FLOAT, "Pick" TEXT, "Player" TEXT, "Position" TEXT, "Nationality" TEXT, "Club Team" TEXT)

Which Round has a Nationality of united states, and a Player of jimmy hayes?
SELECT MAX("Round") FROM table_48043 WHERE "Nationality" = 'united states' AND "Player" = 'jimmy hayes'
SELECT MAX("Round") FROM "table_48043" WHERE "Nationality" = 'united states' AND "Player" = 'jimmy hayes'