Yes! You can definitely add the same Zone in multiple spots on the same page.
However, it’s possible you may end up only seeing your ad once. If that happens it would be because the adserver makes sure the same campaign isn’t shown more than once on a page.
If that’s the culprit you’ll want to be sure to either run ads in separate campaigns, or edit the Zone to “Allow Duplicates”. That will make sure ads appear for you.