Complex sentence: On 30 May 2011 Giuliano Pisapia, an independent close to SEL, was elected Mayor of Milan; on 21 May 2012 Marco Doria was elected Mayor of Genoa.
Split into simpler sentences: On 30 May 2011 Giuliano Pisapia, an independent close to SEL, was elected Mayor of Milan. On 21 May 2012 Marco Doria, another independent close to SEl, was elected Mayor of Genoa.