UCAS parents education

If one of my parents are GOING to university but haven’t attained a degree from it yet what do I put on UCAS where it asks about your parent’s education?

Depends on the exact wording of the question. It used to say the following, (emphasis mine):

"Do any of your parents, step-parents or guardians have any higher education qualifications, such as a degree, diploma or certificate of .."

In which case you would say 'no'.

Yes this is the question I have, they did get one level 3 qualification in something so would I still tick ‘no’?

Yeah, you'd still tick no in that case as a level 3 qualification counts as 'further education' rather than higher.