\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[greek, english]{babel}
\usepackage{alphabeta}
\usepackage{tabularx}
\begin{document}
\section{Ενότητα}
Ο πίνακας~\ref{tbl:1}
         \begin{table}
         \begin{tabular}{|p{0.4\linewidth}|m{0.4\linewidth}|p{0.1\linewidth}|}
                 \hline
                 cell 1 & cell 2 & cell 3 \\
                 \hline
                 cell 4 & cell 5 & cell 6 \\
                 \hline
                  
         \end{tabular}\label{tbl:1}
         \caption{Περιγραφή κελιών}
         \end{table}
\end{document}         
         
