Jira Rest API retrieve assignee displayName

Question

I am using Jira API in Insomnia to retrieve tickets. Now I want to limit the fields returned. One field I want to return is assignee displayName. I have tried many different syntax. I can get the entire assignee object but there is much there I do not want. Here is a sample. I have tried

• assignee.displayName

• assignee?.displayName

• assignee:displayName

  "assignee": {

   "accountId": "xx",
   "accountType": "xx",
   "active": true,
   "avatarUrls": {
       "16x16": "xx",
       "24x24": "xx",
       "32x32": "xx",
       "48x48": "xx"
   },
   "displayName": "xx",
   "emailAddress": "xx",
   "self": "xx",
   "timeZone": "xx"
  

  },

I want to get just displayName from assignee. Does the API not allow this?