If I use a VPN that encrypts my connection **and** a third party DNS like Google's or OpenDNS' (to avoid DNS leaks?), what can my ISP see, exactly? Just me querying the DNS server?

To clarify, I got an account with a VPN provider located in a privacy-oriented jurisdiction. I tested for DNS leaks using [DNSleaktest.com](https://www.dnsleaktest.com/) and it still detected my provider's DNS servers. So I went and changed my DNS servers to Google's ones, just to see what would happen, and it worked, namely, my provider's DNS servers were gone. 

My understanding is, and by all means correct me if I'm wrong, that my traffic goes through the VPN and my DNS queries go through Google's servers, so all the ISP can see right now is me communicating with those servers but nothing more, not the websites I'm reaching, and not the content.