WINONA, Minn. – A Winona driver who police said admitted to smoking marijuana and drinking was arrested on suspicion of impairment.  David Cornell Mitchell, 36, registered a legal 0.04% blood-alcohol level, but officers said he stumbled through field sobriety tests and had blood-shot eyes. Also, officers said, Mitchell’s car smelled of marijuana. He was taken to jail for an advanced test of impairment levels. Mitchell was released pending the return of the advanced test results from the state crime lab. The stop was at Third and Franklin streets about 9:40 p.m.