New fuel sending unit help.

So I recently replaced my fuel sending unit in my 69 Dart. The original fuel sending unit was completely trash. The new fuel sending unit is working perfectly with one hiccup. In the attatched photo is the new unit. The only difference in this one and the factory is an extra tube coming out of the (the straight one that is not bent.) the factory one only had the pipe with the 90 degree bend. I'm hoping for some advice on how to plug up the extra tube as it will cause a
Leak if I fill her up. Any advice is greatly appreciated