External Data Duplicating When Refreshed

I have a sheet that is connected to a external database. When I press refresh to update this data, I get back a duplicate set of data that stacks itself right below the first set. I was assuming that when I press refresh, the data would be updated, not duplicated. I do not have much experience with excel and external data, so I could be missing something pretty obvious. Any thoughts on how to not have this data duplicate when refreshed?