1. Since you have applied for legal heirship certificate with the Tahsildar to declare the legal heirs of the deceased, and the tahsildar has refused the same, the defendant shall the Tahsildar alone.
Moreover since there is no one in sight to claim as successors to deceased, you may publish a publication of the same in the newspaper calling for objections from general public to declare you as the successor to the deceased, which will solve the issue,
2. The municipality if was existing at that time, it may issue a certificate or else you may have to apply for direction to the authorities to issue death certificate before the concerned judicial magistrate court.
3. Once you obtain the above certificates, you may succeed the properties as a legal heir/successor in interest by the order of court..