CREATE TABLE table_203_421 (id NUMBER, "name" CLOB, "from" CLOB, "until" CLOB, "relationship with predecessor" CLOB)

who was the head of the medici for the most years ?
SELECT "name" FROM table_203_421 ORDER BY "until" - "from" DESC LIMIT 1
SELECT "name" FROM "table_203_421" ORDER BY "until" - "from" DESC FETCH FIRST 1 ROWS ONLY