CREATE TABLE table_72100 ("Year" FLOAT, "Division" TEXT, "League" TEXT, "Regular Season" TEXT, "Playoffs" TEXT, "U.S. Open Cup" TEXT)

what are all the playoffs for u.s. open cup in 1st round
SELECT "Playoffs" FROM table_72100 WHERE "U.S. Open Cup" = '1st Round'
SELECT "Playoffs" FROM "table_72100" WHERE "U.S. Open Cup" = '1st Round'