There are a number of ways that you can find out which physical machine your active cluster node is residing on.
You could access the information via the “Failover Cluster Management” console (cluadmin.msc)
Log on to the virtual windows cluster
Open the console “Failover Cluster Management” console (cluadmin.msc)
Drill down through the virtual machine and “Services and Applications” levels until you see your cluster application.
The summary screen will display the current active node under the label “Current Owner”
The benefit of doing things this way are that you can access all sorts of other information about the cluster, however for a quick check it seems quite a long winded way of doing things, a much easier way is to just connect to the virtual SQL instance and run the following T-SQL: