data binding

[fils]

I am pulling CSV back via iron-ajax and I can see in the chrome dev tools it is working.

If I have

 <iron-ajax auto url="URL HERE" handle-as="json" headers='{"Accept": "text/csv"}' debounce-duration="300" last-response="{{ajax3}}">   </iron-ajax>

then binding that into CSV is done how? I tried:

       <csv-preview data="{{ajax3}}"></csv-preview>   

but it seems I am not binding the data in at all. Any guidance on using this data binding?