What traits do they possess?
The top 3 traits, as seen from the research conducted by Kouzes and Posner are:
from the Kouzes and Posner Leadership Model and Book "The Leadership Challenge"
These traits are generally associated with leaders that people would tend to respect and follow.
How do you think a good leader manages crisis under stressful situations?
A good leader should be able to remain calm, and to also keep his group or team calm. He/She should then be able to trace back and look for the cause of the problem, and from there try to solve it. A good leader should also be open to suggestions when trying to handle stressful situations, as he/she may not always have the best idea.