The resumes I've seen from students who have not yet earned a degree tend to run as follows:
University of Somewhere, Computer Science Department, B.S. expected (year):
Coursework includes: (course names go here)
In your case you could add to this:
Additional coursework in Public Administration
People reviewing your resume don't generally care that you spent a year in one department and then changed majors; that's not uncommon. They also don't generally care if you "wasted" a year; they just care what you can do for them now. If that year of education is useful in the context of the jobs you're applying for, include it as just more courses. There's no need to call that out. If it's not, don't.
How do you know if it's useful? For internships (what I assume you're going for) and entry-level positions, you're looking for anything that separates you from the pack, so having another dimension to your background is likely to be helpful in distinguishing you from all your classmates in the same department who took the same courses you did. As soon as you get the degree or have other jobs or internships to list, this first year is likely to drop off.