CREATE TABLE table_203_173 (id DECIMAL, "year ( s ) " TEXT, "serial name" TEXT, "role" TEXT, "co-star" TEXT, "note ( s ) " TEXT, "channel" TEXT)

did he act longer on sinndoor tere naam ka or saat phere ?
SELECT "serial name" FROM table_203_173 WHERE "serial name" IN ('sinndoor tere naam ka', 'saat phere') ORDER BY "year(s)" - "year(s)" DESC LIMIT 1
SELECT "serial name" FROM "table_203_173" WHERE "serial name" IN ('sinndoor tere naam ka', 'saat phere') ORDER BY "year(s)" - "year(s)" DESC NULLS LAST LIMIT 1