Gas is provided in almost all houses in the Netherlands by one of the many suppliers. The main valve is located directly after the gas meter. Everything after the main valve is the responsibility of owner or the tenant. In most cases the central heating and the cooking is gas-fired.
Open all the doors and windows of the room and check if there is a gas leak. It is done as follows:
Does the gas smell remain after the above measures? Or is it not your own device that's leaking? Leave a repair request. In extreme urgency, call the gas provider at 0800-9009. Any costs made by the landlord in case of emergency intervention will be borne by the tenant.