You can use the RangeMax function to "fake" a Zero value and trick the pie chart (with rounding count to the nearest Integer)...
See the attached QFV for details, but you need to add the following to the loading script:
RangeMax(0.00000001, count) as count
Assuming the Data_Raw table contains your original raw data.
And use the num(Sum(count), '##0') as Measure in your Pie-Chart.
It produces the results you need (district FFFF contains 0 counts, but still represented on the chart):
Pie Chart Test.qvf 160.0 K