How to handle long tag elements (30 char+) in Oracle for web services call ?

We are trying to make a web service call from Oracle to update the element "allow-inv-no-backing-doc-from-connect" in Coupa. We can send either true or false for this element. But as the element length is more than 30 character, we are not able to generate the JSON using the below code:

OPEN l_cursor FOR
        SELECT cur_rec.name "name",
               cur_rec.name "display-name",
               cur_rec.supplier_number "number",
               cur_rec.status "status",
               cur_rec.po_method "po-method",
               cur_rec.po_change_method "po-change-method",
               cur_rec.withholding "withholding",
               cur_rec.invoice_matching_level "invoice-matching-level",
               cur_rec.po_email "po-email",
               cur_rec.duns "duns",