As per your post you are from Gujarat. If the house was allotted to your family by Govt. of India after partition and you have been staying there for three generations now, then you can at first check the land records details. For that you need to :
1. Visit the website https://anyror.gujarat.gov.in/ and Click on View Land Record.
2. You will be redirected to page for knowing land records.
3. Submit details about the district, taluka, village and survey number.
4. Enter verification code (captcha) and click on Get Detail button.
5. Land records will be displayed.
If the details mention that the house belongs to you then you can seek help from a local lawyer to help you in the process of registration or if you had any documents but now you cannot find them then if you have the details, if any, then you can apply for getting certified copies.