Apparent fluid leak 2003 Ford Explorer

I have a small fluid leak. Redish in color. The leak point is along the axel area about a foot in from the left front wheel. Right at where the flexible hose that leads to the front left tire starts. In addition, there is circlular shaped black plug (about inch wide) where the leak is occuring. Not a big leak. in the same area towards the right wheel is completely dry.

Brake fluid or power steering? what issues and how quickly should it be repaired.