In whose house at Kiriath-jearim did the ark stay for twenty years?

Answer: Abinadab

The men of Kiriath-jearim took the ark into Abinadab's house on the hill and consecrated his son Eleazar to guard it.

“Then the men of Kiriath-jearim came for the ark of the LORD and took it into Abinadab’s house on the hill. And they consecrated his son Eleazar to guard the ark of the LORD. And from that day a long time passed, twenty years in all, as the ark remained at Kiriath-jearim. And all the house of Israel mournfully sought the LORD.”— 1 Samuel 7:1-2 (BSB)