Table schema:
CREATE TABLE Third_Party_Companies (company_name VARCHAR, company_id VARCHAR); CREATE TABLE Maintenance_Contracts (maintenance_contract_company_id VARCHAR, contract_start_date VARCHAR)

Question: Which company started the earliest the maintenance contract? Show the company name.
SQL: 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