sed -rn '
    /<tr>/ {
        n
        s#<td>([^<]*)</td>#\1#
        h
        n
        s#<td><span[^>]*>([^<]*)</span>.*#\1#
        H
        n
        s#<td><a href=[^>]*>([^<]*)</a>.*#\1#
        H
        x;p
    }
' file

sed -rn '
    /<tr>/ {
        n
        s#<td>([^<]*)</td>#\1#
        h
        n
        s#<td><span[^>]*>([^<]*)</span>.*#\1#
        H
        n
        s#<td><a href=[^>]*>([^<]*)</a>.*#\1#
        H
        x;p
    }
' file 

1988
Mandela, Nelson
South Africa
1988
Marchenko, Anatoly
Soviet Union