Shell script when we need to quote or unquote [duplicate]

Question

I am trying to understand in what situation we should use quote the command while parsing the output from it or when should not.

bash

Case 1:

I am using below command into my bash script which works well while using like below which results the correct output.

$ ssh -i /home/apache.ssh/sshKey root@dbhost01 -o StrictHostKeyChecking=no -o PasswordAuthentication=no cat /etc/redhat-release| awk 'END{print $7}'
6.7

Case 2:

While wrapping like "cat /etc/redhat-release| awk 'END{print $7}'" which results the complete file output and skips parsing though.

$ ssh -i /home/apache.ssh/sshKey root@dbhost01 -o StrictHostKeyChecking=no -o PasswordAuthentication=no "cat /etc/redhat-release| awk 'END{print $7}'"
Red Hat Enterprise Linux Server release 6.7 (Santiago)

Please advise what could be the right approach while using this into bash scripts.