CREATE TABLE table_203_253 (id DECIMAL, "model" TEXT, "frame" TEXT, "years mfg'd" TEXT, "caliber ( s ) " TEXT, "production" TEXT, "barrel" TEXT, "notes" TEXT)

what was the last year of manufacture for these revolvers ?
SELECT MAX("years mfg'd") FROM table_203_253
SELECT MAX("years mfg'd") FROM "table_203_253"