HTML::Template and its derivative HTML::Template::Pro don't support the kind of conditionals you need for that, just simple bools. So what you need to write is

            <select name="province_id" id="province">
                <option value="-1">--</option>
                <TMPL_LOOP NAME="provinceloop">
                    <option value="<TMPL_VAR NAME="id">"
                    <TMPL_IF is_selected>selected="true"</TMPL_IF>>   
+   
                <TMPL_VAR NAME="name"></option>
                </TMPL_LOOP>
            </select>
[download]

And in the the perl code populate is_selected with a true value for the option where id eq current_key.