How can I create a rectangle drill in Orcad Layout Plus 10.3?
It does not appear to be possible to directly create oblong slots in Layout Plus. See this answer on edaboard: 


  Re: create slots in OrCAD
  
  only round type drill holes are allowed in orcad layout plus ( about latest versions i  dont have much ideas). You can provide some special notes in your fabrication layer ( where you include drill table, fabrication notes etc) for the PCB fabricator so that they can cut a plated slot there. I have done it in same boards without issues.


It's directly possible in Altium and other programs such as Allegro.