prova detta :
with table1 as (select $$
-- INSERT YOUR XML HERE --
$$::xml xml_content)
select * from (
select (xpath('value/text()',one_item))[1]::text _value,
(xpath('label/text()',one_item))[1]::text _label from (
select unnest(xpath($$//select[@ref='/uploaded_form_dc8u7x/city']/item$$
,xml_content)) one_item from table1
) a
) b
where _value= ...