It's not that simple.
Having your midheaven in Leo suggests you become known to the public for something Leo-like. But in what way depends on planets in your tenth house, if any (it sounds like there are none), and what message you get from its ruler, which for Leo is the sun. A Sagittarian sun indicates something Sagittarian--knowledge, teaching, interaction with foreigners, philosophy, religion, to name a few things.
But if you're very introverted, you're likely to do introverted Sagittarian things. Maybe you'll write a book. Maybe you'll make yourself known online. Maybe you'll quietly, working on your own, design video games (that would be very Leo). Any of a number of solitary pursuits can lead to public recognition and/or a career.
Having your north node in Aries suggests bringing more Aries type energy into your life. That's not necessarily extroversion, but go-getting, challenge seeking, being ready to stand up for yourself or others if necessary. Perhaps you're inclined to more solitary challenges, or would like to take them on. Anything from solo climbing a mountain to crossword puzzles can be an Arian challenge.
This does not mean you need to leave your introverted ways behind. You would probably be better served by doing introverted things with a fire sign message.