Go to ipleak.net and your current DNS server(s) IP addresses will be displayed. Than you can cross referance the IP with the IP's in the resolvers.csv file. You can also go to opendns.com/welcome and find out if you are indeed using they're nameservers or not.
Another way would be to install wireshark, and start capturing packets. You will see every single packet going through your system. If are using dncrypt without a dns cache, such as dnsmasq or unbound, you will be able to see the IP address of the nameserver, however you should not be able to see the query itself, because it's encrypted.
Of course, there are tools such as dig and whois that you can use to debug DNS related issues as well. Good luck.