After assigning a Hero as your City Official, all of the Hero's attributes will have a significant effect on all aspects of the city's development - building construction, technological research and resource production.

If you need to construct buildings or fortifications quickly or improve resource production you should choose a Hero with a high Politics rating
 
If you want to reduce the time it takes to research technologies, choose a Hero with a high Wisdom rating. 
 
If you want to reduce the time it takes to train troops, select a Hero with a high Bravery rating
 
The higher the Hero's attributes, the more effective their leadership will be.