search for Kings of Babylon

If your goal is to find the names of the kings of Babylon, I don't think that the clause search is the right tool for that. 

Being able to find something through clause search requires that it is referenced in one of Logos' databases (for instance, under People). When you look up subjects and type "Babylon," you can see that "King of Babylon" as a general listing is not listed (at least in any of the resources I have). You can use subject:A king and place:Babylon but then it only searches the Lexham Hebrew Bible and produces only 2 verses (in Hebrew if you can read it), the only two verses where the two terms are found together. So, it does not work.

My suggestion to you is the following: 

1. If you have not do so already (or something similar), do yourself a favor. Set a search parameters as follows on the screenshot below and drag right of your command box to save it. This becomes a quick shortcut for searching these handy categories. 

2. Using that search you may search for "kings of Babylon" (with the quotation marks). Look at the results as "Ranked" to have the titles of your results visible and scroll through them to find any listing in your resources. For instance,

3. If you so desire, go to any of the Bible references for any of the kings, right-click on the name in the verse, select "Person" and use the links to your resources to find other references to individual kings and/or more information about them. You may also navigate to Bible facts to see what you have available on that king.