title: How to find blank within Category in Pandas
body: <p>I am trying to find &quot;Order Number&quot; of the Customer that has been designated a Driver but not for that Order Number. if you see in the screen shot attached</p>
  <p><a href="https://i.stack.imgur.com/OEV3U.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OEV3U.jpg" alt="enter image description here" /></a></p>
  <p>You can See &quot;Ray&quot; that has no Designated Driver as well,but since none of his Orders has been designated a Driver ,I am not looking to get him ,in the following case only trying to get &quot;James&quot; with Order &quot;15&quot;
  Please help
  Thank you</p>