default T13 getOrNull13() {
        return get13().orElse(null);
    }
Returns the 13rd element from this tuple or {@code null} if no such
element is present.

@return the 13rd element from this tuple or {@code null} if no such
        element is present.
common-parent/tuple/src/main/java/com/speedment/common/tuple/mutable/MutableTuple14.java