Anyone using a VPN should test for DNS leaks if they are accessing things online that are let's say sensitive and frowned upon. Windows 10 users especially.
https://www.dnsleaktest.com/
This whole VPN thing needs a little clarity, and to some extent sanity. The purpose of a VPN is to provide end to end secured traffic encompassing the CIA triad, Confidentiality, Integrity & Availability. If you're aim it to access content restricted by region then what we're really talking is here is using a Proxy Server which will make the request for you and return the traffic back.
In terms of DNS leakage, mostly VPNs can be configured to which DNS server they use as Primary, or could even employ split tunnels where some traffic is sent down the tunnel and uses one DNS server for requests or alternatively other defined traffic just goes out 'raw' to the internet and uses public DNS.
The long & short of it is that whichever DNS server handles your request this will be just one in a chain until the IP is mapped to the domain name. So ultimately there may be multiple DNS servers taking a log of requests. So to think a website lookup request is somehow private or can be hidden is naive. Putting it into perspective Google process 4Bn search queries per day, Cisco's recent acquisition of OpenDns sees them handling 8Bn dns lookups per day - data which they fully make use of!
Another thing to consider if you're paranoid about web privacy or just concerned is that connecting to a random Proxy or 'VPN' is not the best way to ensure you're browsing is private. Just who 'owns' the Proxy\VPN and what they do with the data is impossible to know. Maybe GCHQ or Putin is behind the service, who knows.
Anyways, if you want a little privacy and if it's not already mentioned there is always the TOR Browser, and to some extent Google Chromium. Although some nutjobs out there are convinced that the NSA are behind the TOR project but like I said, who knows.....