Find the name of customer who has the highest amount of loans.
SELECT T1.cust_name FROM customer AS T1 JOIN loan AS T2 ON T1.cust_id  =  T2.cust_id GROUP BY T1.cust_name ORDER BY sum(T2.amount) DESC LIMIT 1
SELECT T1.cust_name FROM customer AS T1 JOIN loan AS T2 ON T1.cust_id  =  T2.cust_id GROUP BY T1.cust_name ORDER BY sum(T2.amount) DESC LIMIT 1
[{'cust_name': 'Mary'}]