How to read Assigned To column from SharePoint Workflow Tasks List using Powershell?

I am trying to fetch List details along with associated task columns to export into Excel using PowerShell. I am able to get all columns using following script except Assigned To column to show with which user the task is pending with from associated task list.

foreach ($item in $list.Items |  Where-Object { $_["Approval"] -eq "15"})
{
   foreach($workflow in $item.workflows)`
   {
      if($item.ID -eq $workflow.ItemId)
        {
         $wfName = $wf.Name
         $wfItem = $workflow.ItemName
         $wfPendingWith = $workflow.AssignedTo
         write-host "Title: $wfName  ListItem: $wfItem PendingWith:$wfPendingWith"
        }
    }
}

Can you please point out what am I missing here? Thanks.