If the problem occurs only in a few locations defining the macro \newstylenums
and using it for each number might be enough.
\documentclass{article}
\usepackage{tgpagella}
\usepackage{etoolbox}
\makeatletter
\newcommand{\newstylenums}[1]{%
\begingroup%
\expandafter\ifstrequal\expandafter{\f@family}{qpl}{%
\expandafter\ifstrequal\expandafter{\f@shape}{sc}{\fontshape{n}}{}%
}{}%
\selectfont%
#1%
\endgroup%
}
\makeatother
\begin{document}
abfg 0123456789
\textsc{abfg \newstylenums{0123456789}}
\textbf{\textsc{abfg \newstylenums{0123456789}}}
\textit{abfg \newstylenums{0123456789}}
\end{document}

tgpagella
and the font files, there seems no native support for this. There are lining numerals for regular, regular-italics, bold, bold-italics, but old-style numerals for each combination with small caps. Actually, the fileqpl-hist.txt
of this font mentions: "we are not going to introduce any extensions [...] (e.g., for more convenient handling of oldstyle/normal digits) -- in such cases we suggest using the OTF fonts versions". Since it is not explicitly stated in your question: Is it possible for you to use XeLaTeX or LuaLaTeX? – e-birk Mar 10 '13 at 15:36\usepackage[sc]{mathpazo}
provides lining numbers with small caps though it would not support bold font small caps.... – e-birk Mar 10 '13 at 15:44