I want to have a custom button in the Leads module that can be a single click to filter the list view and only show rows that match a certain criteria (such as "the value of Audience field is Client"). 

I have been able to add a custom button from within Leads->Buttons. I am not sure what deluge script needs to be written in this case.  I have simply written the below, which would filter the data. However, I am not sure how to update the view itself. 

leadsList = zoho.crm.searchRecords("Leads","(Audience:equals:Client)");
return leadsList;