CREATE TABLE table_50556 ("Round" FLOAT, "Pick" FLOAT, "Overall" FLOAT, "Name" TEXT, "Position" TEXT, "College" TEXT)

What was the overall draft pick of the player who was a db and attended college in iowa?
SELECT "Overall" FROM table_50556 WHERE "College" = 'iowa' AND "Position" = 'db'
SELECT "Overall" FROM "table_50556" WHERE "College" = 'iowa' AND "Position" = 'db'