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

who was in office for the most amount of time ?
SELECT "name" FROM table_203_559 ORDER BY "left office" - "took office" DESC LIMIT 1
SELECT "name" FROM "table_203_559" ORDER BY "left office" - "took office" DESC NULLS LAST LIMIT 1