Wladimir Sepúlveda spent nearly six months in a coma
President Michelle Bachelet backs measure
Michelle Bachelet defeated conservative rival in December
Esteban Parada Armijo died in a Santiago hospital on Jan. 30
Country's president-elect supports measure
Alejandro Alfredo Bustamante Godoy stabbed in neck
Country’s Senate voted 28-6 to move measure out of committee
Socialist backs same-sex marriage, transgender rights bill
Same-sex marriage supporter will face Evelyn Matthei in Dec. 15 run-off
Four presidential candidates, European Union ambassador took part
