Which DNS server is used when there are multiple network interfaces?

I have two network interfaces on my computer on my Windows PC.

Primary and Secondary DNS servers are defined per network interface so I can define 2 sets of DNS servers on two network interfaces.

When looking up for a server name, which DNS server is used and why?

As far as I know windows implements interface priority which you could alter. I think it uses the connection with the highest priority, and from there it`s DNS server.