Analog broadcasting ceased to exist in 2007 in favor of digital broadcasting (DVB-T). This is called Digitene: http://www.digitenne.nl
(You'd need a small indoor antenna, or (if reception is bad, but probably not in Leiden), an outdoor antenna.
Ziggo's cheapest offer is Z1 tv: http://www.ziggo.nl/producten/televisie/
This includes analog and digital tv (will need a decoder for digital) for €16,25.
This will get you about 30 analog channels and/or 60 digital ones.