What is the last name of the staff who has handled the first ever complaint?
SELECT t1.last_name FROM staff AS t1 JOIN complaints AS t2 ON t1.staff_id  =  t2.staff_id ORDER BY t2.date_complaint_raised LIMIT 1
SELECT t1.last_name FROM staff AS t1 JOIN complaints AS t2 ON t1.staff_id  =  t2.staff_id ORDER BY t2.date_complaint_raised LIMIT 1
[{'last_name': 'Lynch'}]