Detect holding item

{Item:{id:stone_hoe,Count:1,tag:{display:{Name:Keens Wand}}}}


testfor @p {SelectedItem:{id:"minecraft:stone_hoe",tag:{display:{Name:'Keens Wand'}}}}




Offhand
/scoreboard players set @a nightvision 4 {Inventory:[{id:"minecraft:diamond_hoe",Slot:-106b,Damage:634s}]}

offhand named
/testfor @p {Inventory:[{id:"minecraft:diamond_hoe",Slot:-106b,tag:{display:{Name:"Mobile Phone"}}}]}

/scoreboard players set @a holdingphone 2 {SelectedItem:{id:"minecraft:diamond_hoe",Count:1b,tag:{display:{Name:"Mobile Phone"}}}}

both hands
testfor @p {SelectedItem:{id:"minecraft:diamond_hoe"},Inventory:[{id:"minecraft:filled_map",Slot:-106b}]}