Ask HN: How to take the lead on a project after the head leaves?

I have been working with a senior developer on a project, but now he is leaving and someone has to take the lead. Most likely another senior dev will come on board with me. I would like to take the lead of the project because I know it better (actually the only one who will know it) but I am concerned that it is not enough since I am still a junior. What chances do I have?