These are slight variations from Ryan Sleeper's blog and Andy Kriebel's blog on designing donut chart. Please refer to Andy's blog for the step-by-step tutorial.

By making part of the circle white, it shows a stronger contrast between actual and distance-to-goal.



Example 1: Donut with border
This recreates exactly Ryan Sleeper's design without using a jpeg picture. To make the border appear, you need to click the color mark, and select the border of interest. Note that we need to add border to both outer and inner pie charts.




Example 2: Partial donut 
Without border, the partial donut looks quite interesting. It stresses on the incompleteness of the progress. It's up to you which variation is of interest to you.

To make "Left-to-goal" in white, we need white color in color palette. There is no such color in default Tableau's collection of color palettes. We have to make a custom palette with white color. The trick is to include this code snippet

<?xml version='1.0'?>

<workbook>
<preferences>
<color-palette name="Pure White" type="regular" >
<color>#FFFFFF</color>
</color-palette>
</preferences>
</workbook>

in this preferences file:
C:\Users\<username>\Documents\My Tableau Repository\Preferences.tps

Then we can assign the white color to "Left-to-goal" and make it white.