From 2000 to 2004 he studied postgradually at the Institute of State and Law of the Slovak Academy of Sciences, earning his dissertation in 2004.
After the Velvet Revolution, he was co-opted by Verejnosť proti násiliu (the Slovak counterpart of the better known Civic Forum) as a member of parliament into the Federálne zhromaždenie (English: Federal assembly) in 1990.
He served as the deputy speaker of the Lower House of the Czechoslovak federal parliament (Czech: Sněmovna lidu) in the period 1990–1991.
Ducký, as the former director of SPP (Slovak Gas Industry – one of the most prosperous companies in Slovakia at that time) is the author of the so-called Duckého zmenky.
Valko also was recently representing the state-owned lottery company, Tipos, in a suit in which there is the possibility that the state might lose 66 million euro.