documentclass[11pt,a4paper]{report}
usepackage{
subfigure,
}

begin{document}
begin{figure}[htb]
small
centering
subfigure[label{fig:sub1}This is the first subfigure.]
{
centering
small
begin{tabular}{l}
First sub figure
end{tabular}
}
\
centering
small
subfigure[label{fig:sub2} Second subfigure.]
{
centering
small
begin{tabular}{l c*{2}{p{0.2cm}}}
$a$& 1 & 1  \
$b$  & 2& 2 \
end{tabular}
}
\
centering
small
subfigure[label{fig:sub3} Third subfigure.]
{
centering
small
begin{tabular}{l c*{2}{p{0.2cm}}}
$a$& 1 & 1  \
$b$  & 2& 2 \
end{tabular}
}
caption{label{figure} This figure has 3 subfigures.}
end{figure}
end{document}

documentclass[11pt,a4paper]{report}
usepackage{subfig}

begin{document}
begin{figure}[htb]
small
centering
subfloat[label{fig:sub1}This is the first subfigure.]
{%
makebox[.4textwidth]{begin{tabular}{l}
First sub figure
end{tabular}}%
}
\
subfloat[label{fig:sub2}Second subfigure.]
{%
makebox[.4textwidth]{begin{tabular}{l c*{2}{p{0.2cm}}}
$a$& 1 & 1  \
$b$  & 2& 2 \
end{tabular}}%
}
\
subfloat[label{fig:sub3}Third subfigure.]
{%
makebox[.4textwidth]{begin{tabular}{l c*{2}{p{0.2cm}}}
$a$& 1 & 1  \
$b$  & 2& 2 \
end{tabular}}%
}
caption{label{figure} This figure has 3 subfigures.}
end{figure}
end{document}