begin{document}
begin{frame}frametitle{My title}
  begin{columns}[t]
    begin{column}{0.33textwidth}
    end{column}
    begin{column}{0.33textwidth}
    end{column}
    begin{column}{0.33textwidth}
    end{column}
    col(2){1st text in column 2}
    col(1){1st text in column 1}
    col(2){2nd text in column 2}
    col(3){1st text in column 3}
    col(2){3rd text in column 2}
    col(3){2nd text in column 3}
    col(1){2nd text in column 1}
  end{columns}
end{frame}
end{document}