CREATE TABLE Third_Party_Companies (company_name VARCHAR, company_id VARCHAR)
CREATE TABLE Maintenance_Contracts (maintenance_contract_company_id VARCHAR, contract_start_date VARCHAR)

Which company started the earliest the maintenance contract? Show the company name.
SELECT T1.company_name FROM Third_Party_Companies AS T1 JOIN Maintenance_Contracts AS T2 ON T1.company_id = T2.maintenance_contract_company_id ORDER BY T2.contract_start_date LIMIT 1
SELECT "T1"."company_name" FROM "Third_Party_Companies" AS "T1" JOIN "Maintenance_Contracts" AS "T2" ON "T1"."company_id" = "T2"."maintenance_contract_company_id" ORDER BY "T2"."contract_start_date" NULLS FIRST LIMIT 1