[Tex/LaTex] Label above node in TikZ

Question

I wish to add a label above a node that already contains a label.

\begin{tikzpicture}[scale=0.8,every node/.style={draw=black,circle}]
    \node (a) at (0,0) {a};
    \node (b) at (2,0) {b};
    \draw[->] (a) to (b);
\end{tikzpicture}

The markup above will give me this:

But I want something like this:

Is there any easy way to solve this? I am not looking for solutions using \tikzlibrary{background}

Answer 1

Actually, tikz nodes have text inside and labels outside:

\documentclass{standalone}
\usepackage{tikz}
\begin{document}

\begin{tikzpicture}[scale=0.8,every node/.style={draw=black,circle}]
    \node[label={\small 1/16}] (a) at (0,0) {a};
    \node (b) at (2,0) {b};
    \draw[->] (a) to (b);
\end{tikzpicture}

\end{document}