Is staying after school to help file papers and grade papers a leadership quality?
Not on its own, however, if it is a pattern of behaviour...
volunteering is a leadership quality
making the world a better place is a leadership quality
helping others in need is a leadership quality
doing tasks which lead to personal growth (grading papers) is a leadership quality.
Often, when I evaluate scholarship applications, I look for patterns of these tasks. Doing it one time, or once a semester...not what I want. Doing it often over time is a flag of a person who wants to contribute positively to others, themselves, and make the world a better place. I do invest scholarship dollars into those students, as I (how selfish) am looking for a return on my gift.
Leaders are driven to contribute to make things better, usually by enabling others or helping others, and growing in the task while doing it.