The answer is not as simple as this question. According to me the role will be depend on the work of that project, because no one is perfect in all works which are given to him/her. So we should go with our team and first we should observe potential of all members and give then their work according to their potential. So if we are good in something then we should play our role like a leader otherwise we should learn from others and do the work according to them, because it will make a perfect work by our team.