The original song is "Teče voda, teče (přes velický majír)", variously called a Czech, Moravian or Slovak folk song, so safest may be to call it Czechoslovak, at the risk of offending both nations. Jarmila Novotná's recording of it, made in the 1940s, may be heard on YouTube:
http://www.youtube.com/watch?v=0FWSnrtdZeE

There are at least three different folk songs beginning "Teče voda, teče" (not to mention a number of modern songs with this phrase), so when searching you may wish to use the entire title I've given. Unfortunately, this will overlook some versions where the wording or spelling is slightly different. For instance, the Slovak title is more likely to be "Tečie voda, tečie, cez velecký majer".