I'm going to assume that you've already installed Python, Django, and Node.js on your server and that you have working projects. There are tons of tutorials on installing these on a server, so I'm not going to use this space for that. So let's begin!
First, to create the Django site, upload your Django files to your server. I'm going to save them in the directory /user/web.
To get Django working, there is a great tutorial over at DigitalOcean here: https://www.digitalocean.com/community/articles/installing-django-on-ubuntu-12-04--4
Make sure to follow all the steps. Once you can access yourdomain.com and see your app, you are successful.
Apache is now serving your Django app via mod_wsgi. To serve the Node.js app, we're going to use a reverse proxy pointing to a running instance of the Node.js server on a different port (I'll be using 3000).
Upload all of your Node.js project files to your server. I'll be saving them in /user/web/node.
Now, enable the proxy with the following command:
a2enmod proxy proxy_http
Next, create a file in /etc/apache2/sites-available for your domain such as: /etc/apache2/sites-available/sample.com
In this file, paste the following code, changing sample.com to your domain:
Allow from all
If you need to use another port, change both locations.
Save this file, and then start your node server on the port you specified. Add the site with the following command:
sudo a2ensite sample.com
Make sure to restart your Apache service:
sudo service apache2 restart
Now, when a user visits yourdjangoapp.com, Apache will call your Django app using mod_wsgi as described in the linked tutorial above. When you visit yournodeapp.com, Apache will use a reverse proxy to call the Node.js server running on the port you specified.
You can repeat this process to add as many Node.js projects as you want, but make sure you use a different port for each.
Additionally, I recommend using a Node tool called "forever" (npm install -g forever) to keep your service running in the background and restart it if it crashes.