Can I use an old Edirol UA-5 audio capture as my sound card for the current version of Logic Pro?

The real issue is compatibility with the version of macOS. Did you try to install the latest driver?

With Mojave you may have to authorize Logic to use the Mic in Security and Confidentiality System Preferences.

WD

Unless Roland/Edirol has current drivers, you're out of luck. A lot of my Edirol stuff stopped working a few versions back.

I had the same experience with my Edirol stuff too.

Domhazlehurst: There are old drivers for the UA-5 on the Roland support site. I don't know if they will work on your setup.

Versions of macOS and Logic?

WD