Both are possible (In an If/Then/Else trigger or the trigger's Conditions), but to both: Use the [ TRIGGER ] tags to post triggers. Make the trigger in the Trigger Editor, Copy as Text and paste it here between the tags.
For xAbysSx: Don't use Do Nothing commands in the Then - Actions or Else - Actions. The computer will still count it as performing an action, but it will result into doing nothing. This is only a waste of computer performance. If you leave the Then/Else - Actions blank it will have the same result.