Complex sentence: The 12th ilb took place from 4 to 16 September, the 13th ilb from 4 to 15 September 2013, and the 14th ilb from 10-20 September 2013.
Split into simpler sentences: The 12th ilb took place from 4 to 16 September. The 13th festival edition will take place from 4 to 15 September 2013.