CREATE TABLE table_203_559 (id DECIMAL, "no." DECIMAL, "name" TEXT, "took office" TEXT, "left office" TEXT, "president served under" TEXT, "notable for" TEXT)

how many commissioners served under calvin coolidge ?
SELECT COUNT("name") FROM table_203_559 WHERE "president served under" = 'calvin coolidge'
SELECT COUNT("name") FROM "table_203_559" WHERE "president served under" = 'calvin coolidge'