Requirement to get Project Name in DFF while create Requisition

We have a requirement to fetch the Project Name in a DFF while creating a requisition. As soon as user add the Project Number field the associated Project Name should be fetch in newly created DFF. I have managed to create the SQL based DFF which shows the List of Value of Project Name for the Project Number selected. But the issue is User needs to manually select the Project Name from LOV and it is not defaulted automatically eventhough LOV has only one value. Please can you let me know what action needs to be taken to automatically default