Hi @Chinthakayala Lavanya 

Yes, this is possible. But I would suggest to follow the OOB functionality itself rather than building anything custom here. 

I did check here how the OOB way the platform works in this scenario:

1) Navigate to Asset Table and add a field named as "Purchase Order Line" on your Asset form as shown below:

So add your Purchase order line items and it will be automatically displayed in the related list as well as shown below which you want:

This is a defined Related list and you will not be able to add "Edit" button using List Control here.

Below is the link for the defined Relationship:

https://instance.service-now.com/nav_to.do?uri=sys_relationship.do?sys_id=4061d69c37613000158bbfc8bcbe5d33

Replace "instance' with your instance name.

Hope this helps. Please mark the answer as correct/helpful based on impact.

Regards,
Shloke