Write SQL query to solve given problem: What is the id of the patient who has the longest allergy period?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT PATIENT FROM allergies WHERE STOP IS NOT NULL GROUP BY PATIENT ORDER BY CASE WHEN SUBSTR(STOP, -2, 1) != '9' THEN SUBSTR(STOP, LENGTH(STOP) - 1) + 2000 END - CASE WHEN SUBSTR(START, -2, 1) = '9' THEN SUBSTR(START, LENGTH(START) - 1) + 1900 ELSE SUBSTR(START, LENGTH(START) - 1) + 2000 END LIMIT 1