UL mean more advanced, as in course work offered to students have completed a intro level class in the same discipline.
OChem may or may not count as an UL supplement to gen chem.
General chemistry is an intro level course in inorganic chemistry. Ochem is an intro level class in organic chemistry/biochemistry. Some med schools may expect a UL class in inorganic, analytic or physical chemistry to supplement gen chem.
Again, please consult MSAR and/or directly contact an individual med school to ask. Policies vary widely.
You may find this pinned thread helpful: FAQ Pre-med courses, AP/IB/etc. credit and college/DE courses, etc.