Get the DFF Fields of Purchase Agreement via REST API

I have created a DFF field in Purchase Agreement via Setup and Maintenance page in Fusion ERP. Now when I am getting the data of Purchase Agreement via REST API, response is not showing DFF field value. How can we get DFF value for Purchase Agreement?

REST API : /fscmRestApi/resources/11.13.18.05/purchaseAgreements/{purchaseAgreementsUniqID}