Please provide the age group of any LG Nexus 4 device users.
age group refers to `group`; LG Nexus 4 refers to phone_brand = 'LG' AND device_model = 'Nexus 4';
SELECT T1.`group` FROM gender_age AS T1 INNER JOIN phone_brand_device_model2 AS T2 ON T1.device_id = T2.device_id WHERE T2.phone_brand = 'LG' AND T2.device_model = 'Nexus 4'