CREATE TABLE customer (cust_id TEXT, cust_name TEXT, acc_type TEXT, acc_bal DECIMAL, no_of_loans DECIMAL, credit_score DECIMAL, branch_id DECIMAL, state TEXT)
CREATE TABLE bank (branch_id DECIMAL, bname TEXT, no_of_customers DECIMAL, city TEXT, state TEXT)
CREATE TABLE loan (loan_id TEXT, loan_type TEXT, cust_id TEXT, branch_id TEXT, amount DECIMAL)

Find the name of customer who has the lowest credit score.
SELECT cust_name FROM customer ORDER BY credit_score LIMIT 1
SELECT "cust_name" FROM "customer" ORDER BY "credit_score" NULLS FIRST LIMIT 1