which train ran for the longest time ?
CREATE TABLE table_204_336 (
    id number,
    "operators" text,
    "named trains" text,
    "destination" text,
    "year begun" text,
    "year discontinued" number
)
SELECT "named trains" FROM table_204_336 ORDER BY "year discontinued" - "year begun" DESC LIMIT 1
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: which train ran for the longest time ? ### Input: CREATE TABLE table_204_336 (
    id number,
    "operators" text,
    "named trains" text,
    "destination" text,
    "year begun" text,
    "year discontinued" number
) ### Response: SELECT "named trains" FROM table_204_336 ORDER BY "year discontinued" - "year begun" DESC LIMIT 1